Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767515AbXEDASR (ORCPT ); Thu, 3 May 2007 20:18:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1766895AbXEDASQ (ORCPT ); Thu, 3 May 2007 20:18:16 -0400 Received: from smtpout.mac.com ([17.250.248.173]:64319 "EHLO smtpout.mac.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767494AbXEDASO (ORCPT ); Thu, 3 May 2007 20:18:14 -0400 In-Reply-To: References: <787b0d920704302109r352e6653wc71a0638cbfbdcce@mail.gmail.com> <1178021516.4372.62.camel@daplas> <46375738.1010007@zytor.com> <787b0d920705010849u52a4d6c3o2f1f800521ad5b95@mail.gmail.com> <787b0d920705022317j485cbe26wc83f071834c53584@mail.gmail.com> <787b0d920705030714k3b290d2csa38a5df63c692d6f@mail.gmail.com> <463A42DF.5030409@zytor.com> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Cc: "H. Peter Anvin" , Geert Uytterhoeven , Albert Cahalan , "Antonino A. Daplas" , linux-kernel , aeb@cwi.nl Content-Transfer-Encoding: 7bit From: Kyle Moffett Subject: Re: console font limits Date: Thu, 3 May 2007 20:17:48 -0400 To: Jan Engelhardt X-Mailer: Apple Mail (2.752.2) X-Brightmail-Tracker: AAAAAA== X-Brightmail-scanned: yes Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 36 On May 03, 2007, at 16:16:51, Jan Engelhardt wrote: > On May 3 2007 13:15, H. Peter Anvin wrote: >> Jan Engelhardt wrote: >>> >>>> Put people didn't like that, and disabled text output when the >>>> console is in KD_GRAPHICS mode... >>> >>> at the cost of not getting the kernel oops, heh. >> >> I thought the reason we didn't display text in KD_GRAPHICS mode >> was that KD_GRAPHICS might mean "in a completely different mode >> that only userspace knows about." > > Hrm. Maybe we need a distinction into KD_KGRAPHICS and KD_UGRAPHICS > then. Actually I think the real problem was that "KD_GRAPHICS" got overloaded to mean "some userspace program is probably poking at the GPU in very direct ways possibly including /dev/mem". As such it really isn't safe at all for the kernel to write stuff to the screen in that situation; you could turn a panic()+reboot-after-30-secs into an unrecoverable hard PCI bus lockup. IIRC there were at least a couple chipsets which had that problem with X. If we can implement enough APIs for X to do all of its stuff from userspace without iopl () or /dev/mem then we could probably bring back the option for dumping oopses to screen in KD_GRAPHICS mode, but otherwise it'll just cause more headaches. Cheers, Kyle Moffett - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/